Tommy Sheridan may have convinced a jury that he is neither a liar nor a hypocrite, but he now faces the much more difficult task of persuading members of his own deeply divided party.

The Glasgow MSP, who starts the week £200,000 richer after winning his defamation case against the News of the World over allegations he cheated on his wife, visited a swingers' club and participated in orgies, is understood to be planning to stand again as leader of the party he co-founded. But over the weekend opposing factions were preparing for war, with a splintering inevitable.

Sheridan's supporters have already formed a grouping known in the party as the SSP Majority. It includes the Socialist Workers' Party and Committee for a Workers International. They are calling on those who gave evidence against Sheridan to quit. During an interview on Radio 4's Today programme yesterday, Steve Arnott, party organiser for the Highlands and islands, said the 11 witnesses represented a minority faction with 'positions of influence beyond what their numbers probably deserve'.

As a witness for Sheridan, he suggested up to 150 people in the party could be 'deeply delusional'. His former leader was one of the 'most iconic socialist leaders' in the postwar period, he said.

These 'delusional' members have formed a rival faction, United Left, including co-founder and former close friend of Sheridan, Alan McCombes, and MSPs Carolyn Leckie, Frances Curran and Rosie Kane.

Leckie told The Observer that all whose reputations had been tarnished would welcome perjury charges as a chance to clear their names. She said she no longer regarded Sheridan as a socialist and would raise the matter at today's executive committee meeting. Leckie, along with 11 other senior SSP members, told the court that Sheridan had admitted at a private party meeting he had visited a swingers' club and apologised for it, but had said he would deny it publicly and sue the News of the World because there was no proof.

During interviews on Friday, the current convener, Colin Fox, tried hard to convince people and probably himself that following their 'healthy disagreement' party members could now kiss and make up. 'The urgent task is to refocus the SSP around our shared political objectives,' he said. Fox, an ally of Sheridan, had also told the court of a private confession. He later called Sheridan's victory an 'extraordinary achievement against heavy odds'. 'Every socialist will rejoice in the jury's rejection of the News of the World's journalism,' he said. The paper plans to appeal against the verdict, which it called 'perverse'.

On Friday afternoon, after the verdict, a jubilant Sheridan raised his fist and thanked the working-class people on the jury. The crowd cheered in unison and repeated his trademark gesture.

During the trial, the jury was enthralled with the one and a half hour speech of Sheridan, a marvellous orator who sacked his legal team halfway through the case. Many had thought it a suicidal move. But he revelled in the role of Sheridan QC, while dispensing with legalese and court procedure. He cast himself as a working-class hero fighting alone against the legal establishment and a global media empire concerned only with sales.

He provoked laughter among jurors when he offered to disrobe to prove his wife's claims that he had a hairy body. His voice trembled when he accused the Sunday tabloid of endangering his unborn baby's life with its lies, and wiped away a tear as he professed his love and adoration for his glamorous wife, Gail.

On Thursday afternoon the judge, Lord Turnbull, told the jury that if they believed even one witness about Sheridan being a swinger or adulterer it would be enough to find in favour of the paper. In total 18 witnesses, excluding those from the News of the World, gave evidence to this effect. But after two and a half hours' deliberation the jury effectively branded them, including three MSPs, as liars and perjurers.

Sheridan, in a seven-page spread in yesterday's Daily Record, hailed his wife's evidence as a key factor in his victory. He admitted that he had always been a flirt and was vain. With his shirt unbuttoned and his hairy chest gracing the front page, he told the paper: 'My wife sticking by me was probably the most important factor ... she is an honest woman who has worked her whole life and has not been prepared to lie on oath.'